Researching Blue Carbon – meet Allan Audsley
A new Scottish Government funded research programme into Blue Carbon began earlier this year as part of a commitment in the 2017-2018 Programme for Government. The current focus revolves around measuring the ability of various habitats to sequester carbon, understanding how it is stored for the long term, and building an evidence base on the effects that human activities may have on these process. To support the programme, the Scottish Government has sponsored a number of PhD students and Marine Scotland has just established the Scottish Blue Carbon Forum (SBCF), which will be made up of the students and supervisors of the studies, as well as external stakeholders and Scottish Government climate change colleagues.
In this series of blogs, we will be introducing you to each of the students and letting them tell you more about their work.
Next up, Allan Audsley.
My PhD project, funded by the Marine Alliance for Science and Technology Scotland (MASTS) and Scottish Natural Heritage (SNH), is jointly supervised by Dr Tom Bradwell (Stirling), Dr John Howe (SAMS) and Prof. John Baxter (SNH). Pockmarks are formed due to mobile fluids within the sediment rising and entering the water column. Within this fluid, gases such as methane and carbon dioxide can be dissolved or exist as free gas bubbles. This gas was formed through microbial activity breaking down the organic matter that was deposited over thousands of years; this is referred to as ‘blue carbon’. Pockmarks represent an important marker for sites of blue carbon and act as gateways for it to re-enter the carbon cycle. However, the spatial distribution and activity status of pockmarks in Scottish waters is currently unknown. My PhD project aims to determine the morphological characteristics of pockmarks within fjordic settings around Scotland’s west coast in order to determine pockmark significance towards the carbon budget.
Hundreds of these pockmarks have been observed within sea lochs across western Scotland, many of which are over a hundred metres in diameter and up to seventeen metres deep. Pockmarks can be found either forming in long linear strings or in what appears to be random scatterings. Due to this wide variety in shape, size and distribution patterns it is essential to research how they are classified. The shape and size are a result of pockmark activity and the environment they have formed in. By investigating these factors we can begin to shed light on the formation of these features.
Seismic surveys carried out across Scottish inshore waters can allow us to study the sedimentological structure of the seabed. It is within these records that we can also observe gas, which has a variety of acoustic signatures. It has been shown that the variety of these signatures can show differences in how the gas is distributed in the sediment. Research into the distribution of gas rich sediment and the geological history of the region will help to not only quantify the free gas present within Scottish waters but to also build a picture of the formation mechanisms and history of pockmark activity.
Scotland’s fjords and sea lochs represent very important sites of sub-seafloor shallow gas and mobile fluids. The seafloor around Western Scotland has been shown to be a significant reservoir for stored ‘blue carbon’. Pockmarks are the clearest seafloor expression of geologically recent fluid escape from the subsurface to the ocean. This research will go towards furthering our understanding of the Scottish/ global carbon cycles. Other stakeholders also have an interest in this research: especially regarding the designation of marine protected areas; the siting of offshore infrastructure; and the biodiversity of benthic fauna.